LP, actually we do have an Osprey that hangs out for a couple of weeks each winter. It fishes in the river with the herons, fascinating to watch it fish. The river is only about 400 feet from the house. There are no large trees near the house, so I'm hoping the osprey will stick with the river, since there are large trees it can fly to after a catch there. Also, one of the primary purposes for the moat is to eliminate the need for a fence. Our house is in the middle of our pasture. I need something to keep the goats out of the yard, and a moat seems aesthetically more pleasing than a fence, which would intrude on our view of the river in back, and the 2 acre lake in front of our house. Goats won't walk through mud if they can avoid it let alone standing water. We have livestock guard dogs (Great Pyrenees and Anatolian Shepherds), and they are not too approving of any large bird flying over the pasture or landing in an area they can get to. They will usually run underneath them until they exit the property. Some buzzards were trying to get at a placenta (it is kidding season right now) the other day, but had to go look for an easier meal because the LGD's wouldn't let them land long enough to eat. The herons and osprey will probably have the same problem. During the summer I expect the dogs will swim in the pond, will that cause a problem? Azponder, your points about contractors are well taken. I just spent 2 years building this house, and I do mean building it. I did most of the work myself or hired my own crews because I either couldn't find contractors or had to fire the ones I hired. By the time we finished I was beginning to wonder if I spoke some strange dialect of english that most contractors couldn't understand. I have a very good idea of what I want from the pond, I'm just not entirely sure how to get there. As I've been doing more research it has become apparent that what is necessary/desirable for a small pond is not necessary or desirable for one as large as I am planning. My contractor told me I wouldn't need any filtration, just to keep the water moving, and I'm gathering for the pond I envision he is probably correct. If you think about it, the pond I am building is the size of a lot of golf course lakes, and most of those I am familiar with are pretty clear without using any filters even though they have fish, turtles, frogs, etc. Does anybody here have experience with a pond this large that could provide some feedback?

Waterbug guy, First I will talk a little bit about concrete in water. You say it is a myth that concrete in water can kill fish and raise the PH. When concrete first sets up the surface PH is 12.0. Which is the same PH as a drain cleaner called "draino". As it is exposed to the CO2 in the air the PH goes down. But water is a very good leaching agent and so water will continue to try and get the chemicals out of the concrete. So will the PH in the water be raised? If the water has normal PH of 6.5 to 8.5 the answer is yes. The real question should be "how much will it raise it"? That question isn't easily answered as there are a lot of variables. Just to list some the age of the concrete, the condition of the concrete, is the water flowing over the concrete, the natural PH of the water, is the water being changed, and the volume of the water versus the contact area of the concrete. In some cases the rise might be so low as to make it very difficult to measure. But in other cases it can and does raise the PH to 9 to 9.5. At these levels it can and does kill fish. If I remember correctly you have stated that you are a pond contractor. If you are I hope you having started using roofing liner in the ponds that you build. Most of the time a person on this forum is never going to have a problem with roofing liner. Can there be a problem with roofing liner? This should be the question. The answer is yes. The chances that there could be a problem is very low. The largest pond product manufacturer in the US sent out a letter to all their customers a number of years ago. This letter said that all their liner in the future would be tested to be fish safe as they got a batch in that was not. In other words they were selling roofing liner as pond liner. This company had been selling a lot of liner for 10 years before this problem. If it had happen today with the wide use of the internet I would have think that some lawyer would have gotten this information and started a class action lawsuit against them and they would be out of business. The lawyer could easily have sued them not only for the cost of the liner that they had sold but for the cost to replace all those liners in the ponds built with them going back to the first time they sold this liner. The largest liner manufacturer in this country has told me that almost never would you ever have a problem with roofing liner but you might. I think that as a contractor you can't take that chance. If you were unlucky and did have a problem and were sued over that problem the lawyer handling the case would find out that they would sue for every customer that you have that has this liner. In other words you would be out of business. So is roofing liner toxic? No most of the time. But there is a small chance that there maybe a problem. I have only talked about 2 of the 8 things that you listed. I could easily talk about many of the other things listed but my point is this. You listed these things as black and white but they are not black and white. The only thing that is black and white about ponds is that all aquatic life will die. Mike

dang it....I had a really well though out response all done, and my internet explorer crashed. So I'll try again...lol!! First...a few comments regarding how koi ponds compare to aquariums. Normally, aquariums are lightly stocked with small fish. It's really easy to keep the ammonia/nitrite/nitrate cycle operating perfectly in a correctly stocked environment. Same as a rock bottom pond...lightly stocked and properly maintanied it can work. In a pond's bio filter, ammonia is converted to nitrite and then to nitrate. Nitrate is most easily removed froma koi pond by way of regular water changes. Ever try to keep an aquarium with goldfish? Many goldie keepers I know keep no gravel in the tank at all, because of maintenance. That gravel gets really filthy very fast. I had a lovely goldie tank once....and gave it up. the maintenance was a nightmare! I'd rather deal with a huge koi pond any day of the week. Some people are reporting sucess with rock bottom ponds and no maintenance. Again...it is directly related to stocking levels. I hope these ponds continue to perform well for years to come, but for the vast majority of people, they will not. Most watergardeners install their ponds (and rocks) and then run out and buy a bunch of adorable little 5" long koi. The koi grow.....fast. They produce mountains of fish waste, which all gets trapped in the rocks. But because the pond looks clean, the owner is lulled into a false sense of security and does not think that there is a thing wrong, until the fish start dying or the fins start rotting off. Then they do one of two thing....they learn where they went wrong and correct their mistakes, or they just buy new fish (which is unfortunatly what most people do). Matt...you are on the right track with your new pond. You certainly can install your bottom drain now and add the rest of the system later. But instead of using a pipe cap, install a 4" ball valve on the end of the line. The water can't be permitted to sit stagnant in the unused drain line for too long or it will start developing the dreaded hydrogen sulphide gas. Opening that valve every couple of weeks and allowing the water to flow out for a couple of minutes will prevent the problems. I am attaching a link to the Atlanta Koi Club's web site. They have an excellent pdf that explains a lot about how a koi pond works, water quality, stocking levels, how much biofiltration is needed and many other wonderful facts. Cindy

Gatormom, I have container water gardens all over the place. They never turn into stagnant, mosquito infested messes. Once you have the plants balanced (not hard to do) and a couple of guppies in them, they are good to go. The guppies eat the mosquito larva, and the oxygenating plants keep the water relatively clear. You can top it off every other day or so, or even run it over a bit, if you want to change out some of it. I never use pumps or filters on my urns and tubs that I raise pond plants in. Here are a few pictures for you to see what I mean: This is a large, galvanized tub that I keep taro, rush, papyrus and dwarf water lilies in. I add black food coloring to make the water look deeper and more reflective. It also keeps algae growth down. This is an urn I had a potted canna in last year. You can see that I had hornwort floating in the water. (You can buy it at any aquarium place, including PetSmart.) It is a good oxygenator, and it gives the baby guppies (and there are always baby guppies) somewhere to hide. Here is the canna I'm growing in the urn this year. It really is not as hard as you might think, and during the summer, it is especially nice, because the plants never wilt or dry up. I plan to add several more container water gardens around the yard this year. I'm going to sink a big black tub in the ground and grow a lotus in it. Marcia